Published 2026-06-05
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Genotypic characterization of bacterial strains obtained from leaf cheese using real-time PCR

DOI: https://doi.org/10.22490/24629448.11772
Nadia Catalina Alfonso Vargas University of Boyaca image/svg+xml
Astrid Maribel Aguilera Becerra Pedagogical and Technological University of Colombia image/svg+xml
Martín Orlando Pulido Medellin Pedagogical and Technological University of Colombia image/svg+xml
Luis Miguel Borrás Sandoval Pedagogical and Technological University of Colombia image/svg+xml
Claudia Patricia Jaimes Bernal University of Boyaca image/svg+xml

Objective: To genotypically characterize bacterial strains isolated from queso de hoja (peeling cheese/soft white cheese wrapped in leaves) samples from the Hoya del río Suárez region, Colombia, using Real-Time PCR (qPCR) for the detection of specific virulence genes. Methods: A total of 58 bacterial strains (15 Salmonella sp. strains, 15 E. coli, 8 S. aureus, and 20 Listeria sp.), previously isolated from queso de hoja samples from the Hoya del río Suárez region, Colombia, were analyzed. Genomic DNA extraction was performed, and genotypic characterization was conducted using qPCR with primers for the eaeA, nucA, hlyA, and invA genes, respectively. Results: The standardization of the methodology was successful, achieving high efficiency and linearity. Regarding amplification in the samples, it proved to be highly effective: 73.3% of E. coli strains were positive for the eaeA gene, 100% of S. aureus strains for nucA, and 100% of Listeria sp. strains for hlyA. The specific modifications observed in the melting curve could suggest the existence of possible allelic variants in these strains. However, the absence of invA gene amplification in the 15 Salmonella sp. strains indicates the need for a future exhaustive molecular evaluation of these isolates. Conclusion: The successful standardization and genotypic characterization of the strains using qPCR was achieved, validating the methodology for the detection of virulence factors in bacterial isolates from queso de hoja.

keywords: food contamination, bacterial DNA, food cReal-Time Polymerase Chain Reaction
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How to Cite

Alfonso Vargas, N. C., Aguilera Becerra, A. M., Pulido Medellin, M. O., Borrás Sandoval, L. M., & Jaimes Bernal, C. P. (2026). Genotypic characterization of bacterial strains obtained from leaf cheese using real-time PCR. NOVA Biomedical Sciences Journal, 24(47), 67-86. https://doi.org/10.22490/24629448.11772
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